So I think it really is something that you need to be born with. Like I said before, classes and reading will let you hone the skill, but if you don't have the talent to begin with I think you are pretty much out of luck. If everyone could take some art classes and draw like Chip Foose, Kenny Youngblood, and many of the other talented artist, the world would be flooded with them!

Learning to draw like Chip Foose, Kenny Youngblood and just about anyone that is an accomplished illustrator of cars is not something you will learn from a few art classes, but like any apprenticeship, if you start with the basics you can end up with an acquired skill and this is more likely to happen if you are under twenty than if you are already involved in life with a young family and job responsibilities. I'd like to encourage anyone that wants to improve their chances from whatever their basic skill or talent is presently. Don't be fooled into thinking that because someone has an eye for detail or perspective or ten years of practice under their belt that you should just throw in the towel. Most have been encouraged from an early age and have spent countless hours working on perfecting their skills but if you start out with the best helps and put your mind to it, you can learn more than conventional wisdom will admit. One of the books that I had in mind is published through Airbrush Action Magazine. You can go on line at www.airbrushaction.com and I haven't kept up with their mag but several years ago they were advertising a paperback titled "Cartooning" by Don Edwards. I checked out Amazon.com and they had it but listed it for around $75. as a collector's item. It was advertised in the mag for $12.95 in '98. It looked like an excellent place to get started and with all the help from any books of this type, the most common failure is to try to take short cuts or leave out steps in the process and not follow to the letter what ever is being taught. This will usually end in discouragement. There is no fast way to become proficient in something like this "or there would be a world flooded with accomplished artists." Believe it can be done and put in the required effort. I've seen it happen.
That link to roadsters.com from Malc certainly has some inspiring work and there may be some place there to find help but most of the work is finished and not a how-to presentation. I also found Airbrush Action to have some good information although it was more advanced than just the basics however there was a fair bit of emphasis on cars and bikes as well as general illustrating.